Explain these 747 condensation patterns?

[SMOC]

On this pic you can see several distinct patterns created by the A/C.

One around the nose
Trailing edge of the left wing
Plus faint ones around engines 3 and 4.

Anyone seen anything like it before?

JetPhotos.Net Photo » N703CK (CN: 21939) Saudia - Saudi Arabian Airlines (Kalitta Air) Boeing 747-212B(SF) by gerard isaacson (http://www.jetphotos.net/viewphoto.php?id=6472254)

[Lafyar Cokov]

The nose/engines ones looks like early on-set of a sonic shock wave - but I would imagine that under reasonably normal atmospheric conditions the aircraft would have to be doing about M0.85 is for these to start to form. Not sure what Vmo in the 742 is but I would have thought this to be rare - although low air pressure may aid the formation of these effects.

See this (http://www.whatsnextnetwork.com/technology/media/Jet_shock_wave.jpg) for an image of the later development of a wave.

[forget]

My guess - nothing to do with the 747, but high altitude fighters.

[The Yank]

Mmo on 742 is M.92 normal cruise M.83 to M.86 :}

[Centreline747]

Forget; I would tend to agree with you there, a clever picture.
Mmo on the 'classic' is 0.92 and I understand the airflow begins to go 'supersonic' over the 'hump' first at a little over 0.92 (sorry I cant find a published figure but believe it is around 0.95) What sort of wave that would create would be interesting to see.
I have been up to 0.94 on a test flight (to function the overspeed warning, before you all start jumping) and cannot say I noticed much different apart from the increased airflow noise.:)

Rgds

CL747

[lomapaseo]

Well I really believe that this kind of discussion is more suited for the spotters forum.

I would query the photo details before even touching the question.

With that kind of clarity it probably is below 10k and thus the speed no greater than 250kts

[PETTIFOGGER]

I will have a light-hearted go at this. No idea what caused the 'ring', but I would guess that the apparent side lobes around no.4 engine are vortices generated above the wing by the use of the speedbrakes. Similarly, the line of condense behind the port wing is the remix of flow which has been displaced further aft by the boards. The a/c is descending and is probably no higher than 5,000ft (going by the lens used). I am not a spotter so I could be wrong! Looks like a low morning sun which would suggest a heading of south-east.

[downwindabeam]

Could almost guarantee a/c is below 10kft, since the recognition lights are on.

Zoom in, you'll see it clearly.

Also if you zoom in around the FO wing forward part, right infront engines 3 & 4 you'll see a blue 'cut line' maybe?

[spannersatKL]

Wheres No2 Air con Pack Ram Air Inlet, appears to be missing!! Its an SF so would have been born with all 3, unlike an F.....Also IF one pack had been deleted then would have been no 1 or 2 pack......strange, possibly photo shop job? ....

Also aren't the indications behind no 3 and 4 engine the upper wing surface shock wave being shown. The one for the left wing being hidden from the camera angle?

[first_solo]

Could it be a vortex of a previous aircraft?

[helldog]

Not sure what engines this beast has but with Q engines, and I believe the 7R4G2, above about 25000' if you let the N1 drop below 60% air 'sipilage' out of the front of the engine. Now this photo looks like it shows an aircraft flying lower than 25000'. However if it was going much faster than a normal descent the same might happen, I dunno.

The one on the back of the wing I think is common to see, but you often see a sheet of condensation, perhaps for some reason we only see the outline on this photo.

The one on the nose? I dunno.

[Centreline747]

......sorry Guys and Girls I still believe that it is a clever picture and the "lines' in the sky are much higher than the 747, and as suggested by forget in post 3 have been made by high altitude fighters. Fair play to the photographer :D

Look like Q engines to me.

Rgds

CL747

[Capt Fathom]

Wheres No2 Air con Pack Ram Air Inlet, appears to be missingDon't know what photo you guys are looking at, but I can clearly see 3 pack inlets!

[Centreline747]

Yes all 3 are there - well spotted :ok:

Rgds

CL747

[olepilot]

forget & centerline,you are right

[TeachMe]

Not sure, but could the ring in front of the nose have something to due humidity and dew point? Something akin to a lenticular cloud (en.wikipedia.org/wiki/Lenticular). Just an idea, perhaps stupid!

TME

[Rainboe]

It's either a photoshop hoax or contrails from other aeroplanes (military aerobatics most likely). I have never seen or heard of such contrails being formed. They are nothing to do with that 747.

[helldog]

Just tried to contact the photographer to get him to come to pprune to talk about his photo, but for some reason the message is failing to send....someone else care to try? Would be interesting to hear about the conditions in the day etc etc from the guy that snapped this photo.

[Coffin Dodger]

With 30 years imaging experience and a lifelong interest in aviation, in my estimation that pic is the result of some pretty bad photoshopping. Given five minutes tomorrow I could probably replicate the effects in that pic rather easily.

Firstly, the 'shock wave' is completely non-symmetrical. (i.e. shaky hand on airbrush tool via mouse/graphic pen). Secondly, it starts about one or two metres back from the nose of the 747. It is also disproportionately wide relative to the aircraft.

Those with a better grounding in physics than I might know better, but surely this would require a ridiculously high speed or some sort of very humid/dense atmosphere,

My money's on 110% fake.

[yaarpanjabi]

The photo can't be real, if that's a shockwave, the condensation should not protrude forwards from the wave but backwards only as the air pressure decreases rearwards. That has to be a cirrus cloud.

[olepilot]

These contrails have nothing to do with the 747.
They are produced by a military jet or two.

[Brian Abraham]

What the photographer is saying now on the link.
Posted by gerard isaacson on January 31, 2009

To help shed light on this picture, a storm had just cleared the area, I shot this around the same time USAirways #1549 dropped into the Hudson. This 747 cleared the view of the sky in my back yard like the space schuttle. The halo appeared once very faintly which drew my attention, so I raised the camera in case I saw it again, the first halo last like 1/2 a second, then I started to see it again so I depressed the shutter once...just one shot...that's what I got...the halo or shockwave moved with the plane...it did not pass through a vortex donut so to speak...it was 11 degrees on the ground so I think possibly this is light playing off a layer of ice crystals where the air is compressing by the bow wave. I've just never seen this before. I wonder if the crew were able to see it?..

High magnification would lead me to believe it's photoshopped as you can see where the pen to draw the "Condensation" has stopped and started, for one thing. Other anomalies can be noted as well, lack of symmetry and continuity. Edited to add: Bollox to veracity, it just ain't how the Prandtl–Glauert singularity works (which is what the photographer is trying to say is going on).

[RingwaySam]

Guys comeon, have a little respect for the photographer - Trust me, if it was a fake that photographer would be banned by now - The screeners at JetPhotos are very experienced and if it was a fake the photographer would have been banned immediately - Nobody seems to know what the effect is, which is fair enough but theres no need for saying it's a fake. What makes it even worse is someone has posted a comment on the shot, and it sounds like it's from here.

Posted by Mmmmmmm on February 1, 2009

Photoshopped, and not very well done at that. Professional airline pilots on another site are having a bit of a giggle. Sorry gerard.With 30 years imaging experience and a lifelong interest in aviation, in my estimation that pic is the result of some pretty bad photoshopping. Given five minutes tomorrow I could probably replicate the effects in that pic rather easily.

I'd be interested to see this if you still don't mind having a crack at it?

[forget]

With 30 years imaging experience and a lifelong interest in aviation, in my estimation that pic is the result of some pretty bad photoshopping.

Here you are Coffin Dodger, a canvas (http://www.airliners.net/photo/Thai-Airways-International/Boeing-747-4D7/1461121/L/&tbl=photo_info&photo_nr=65&sok=keyword_%28%5C%27%2B%5C%22747-200%5C%22%5C%27_IN_BOOLEAN_MODE%29%29_&sort=_order_by_photo_id_DESC_&prev_id=1461548&next_id=1461078) for you. Standing by.

[Rainboe]

Fake or not, those contrails are nothing to do with the aeroplane. Period. People do this sort of thing for notoriety- like the 747 apparently climbing vertically from nose-on out of LAX.

People are mugs if they think they can come to a prof flyers forum and fool people with this nonsense. I have never seen condensation patterns around a jet like that. The condensation that day is non existent. It's fake, or a snap at an instant when those trails were at altitude....in which case the photographer is being disingenuous.

[Coffin Dodger]

Forget.

That 'blank canvas' is a copyright image and really I shouldn't be tampering with it at all, but I hope the author won't mind me adjusting just a little selection of it.

Could be better if I spent more time on it. Or if I was doing it for money. :}

http://i557.photobucket.com/albums/ss15/CofDodger/blank-canvas_selection.jpg

[RingwaySam]

Nice effort Coffin Dodger - I still think the other is real and looks more realistic but that's just my opinion. If you look through his shots I think it's obvious he doesn't need to cheat to gain views.

Fake or not, those contrails are nothing to do with the aeroplane. Period. People do this sort of thing for notoriety- like the 747 apparently climbing vertically from nose-on out of LAX.

That's fair enough Rainboe - As for the 747-400, I didn't see the picture but if there was noting in the backround then it's fairly simple to do. Even somebody with no Photoshop experience or editing experience could do that. Needless to say, it didn't stop these Malaysian pilots giving it ago...
Photos: Boeing 747-4H6 Aircraft Pictures | Airliners.net (http://www.airliners.net/photo/Malaysia-Airlines/Boeing-747-4H6/0895363/L/)

:E

[Coffin Dodger]

I probably tend to agree now. Confess to having partaken of several glasses of a rather pleasant Pinot Noir when I wrote my initial post. Naughty but nice.

Later analysis of the pic does lead me to conclude that yes those contrails in the original pic could well be real. In the line of sight but well behind and away from the aircraft.

Hey at least I rose to forget's challenge though.

And now, not being an aviation professional I think I'll go back to lurking.

[Brian Abraham]

but theres no need for saying it's a fake.
Absolutely every reason to call it a fake. The photographer in his own words explained

"The halo appeared once very faintly which drew my attention, so I raised the camera in case I saw it again, the first halo last like 1/2 a second, then I started to see it again so I depressed the shutter once...just one shot...that's what I got...the halo or shockwave moved with the plane...it did not pass through a vortex donut so to speak...it was 11 degrees on the ground so I think possibly this is light playing off a layer of ice crystals where the air is compressing by the bow wave"

His statement makes it very plain that there was no upper level cloud or a contrail put down by another aircraft, and the halo moved with the aircraft.

Coffin Dodger, your reproduction would be more believable (though its still obviously fake) than the original if you were attempting to bluff the uneducated. The original is so fake its unbelievable that anyone with a modicum of aeronautical knowledge could be sucked in.

like the 747 apparently climbing vertically from nose-on out of LAX

Rainboe, if its the photo I'm thinking of its certainly a dramatic shot. Was taken by a highly respected aviation photographer who explained exactly how he got the shot (use of particular lenses etc - not a subject I'm much up on). Think it was in an AW&ST magazine photo contest. The same type of photo is often seen in aircraft advertising.

[Rainboe]

That's the fellah. I recall the frustration of trying to tell people it wasn't really a vertical climb and it had been 'manipulated'.

[Brian Abraham]

Here's your photo Rainboe. Actually it hasn't been "manipulated" and if you look at the runway signs you begin to get some sense of perspective (angle of climb). The foreshortening effect of the telephoto lens adds to the drama.

http://cdn-www.airliners.net/aviation-photos/photos/3/5/8/0640853.jpg

[Pugilistic Animus]

looks like a cirrus cloud taken at a strange perspective---if it were aerobatics, that's like a 10G loop:\

if it were real the wing would be flapping like a seagull:}

[midiron]

Just my geeky perspective, but let us look at what seem to be the facts:

1) These patterns APPEAR to have color, which implies something optical. The Prandtl-Glauert Singularity just produces vapor. Such vapor sometimes does produce color, but also tends to appear in a conical shape. Prandtl also predicts a radius much, much smaller than what we see in the photo.

2) P-G concerns the separation and re-attachment of airflow at high Reynolds numbers (which need not be transonic), but the patterns we're seeing do not seem to result from detached flow, especially when you consider the asymmetrical ring around the nose. In addition to the evident color, please also note that this ring around the nose seems to be almost actually TWO rings. The second one, sharper and less cloudy, looks like it is just forming/becoming visible.

3) Just assuming for argument's sake that there is some kind of P-G effect, what about the shapes we're seeing behind the left wing and ahead of the right-wing pods? Seems like a totally different kind of effect, and not at all related to the classic "N" shape shockwave that is predicted and well-observed. Also, we know that transonic waves will creep up from behind the trailing edge, but this airplane is flying much too slowly for that. At approximately 5,000 feet, this airplane is doing probably 0.2 Mach. We sometimes see condensation developing below and behind extended flaps at such speeds, but this aircraft is clean and we know that it was a cold day (-11C), so ice crystal formation (sublimation) is more likely than condensation.

4) We should also consider what is NOT. Maybe the aircraft in the photo is nowhere near the actual phenomena. Looking at it, the Boeing appears to be above the bow shape, yet far below the trailing edge shape. The pod shapes seem to vague to judge, but all three shapes seem to have a similar intensity and coloration.
5) Also missing are the wingtip vortices often visible in high-humidity conditions. If we were dealing with a P-G effect, then we would expect to see tight vortices coming off the wingtips.



6) Related to 4, maybe it is flying THROUGH some kind of ring-shaped vortex created by a factory or a local explosion of some kind (these are well-documented), but the photographer claims to have seen the phenomenon actually repeat itself, which is why he said he raised his camera in the first place. If the effect repeated itself, the aircraft was not flying through an existing vortex. UNLESS it, by some massive coincidence, managed to re-enter or remain in wake turbulence from a preceeding aircraft. Could be, and I've seen it happen.
7) The bow shape resembles a parhelic circle. These usually form at a 22 degree angle between the observer and the object, which is plausible here, but how to explain the non-circular shapes ahead of the right wing and behind the left one? Again, potentially two different effects.

Just a little comida for thought,

m.

[proxus]

Looks believable to me except that the photographer says that he forgot to switch to "raw" on his camera. That is quite convenient statement because raw data from the camera can't be tampered with. Jpeg can be tampered with and have every EXIF info edited.

My 2 cents.

[soon7x7]

Hi, I just stumbled upon an argument of sorts over an image I photographed back in 2009 of a Kalitta 747 with strange compression rings around the airframe. Many had theories, some accused me of photo shop work just to get noticed. If any of you are interested in this photo I would be delighted to enlighten you about it. It is unique, no doubt. And it was purely, 110% undoctered...g